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root:loadtext [2010/11/09 16:33] – created nchiap | root:loadtext [2010/11/12 15:09] – nchiap | ||
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To read data from a text file into a tree all you need are the following two lines | To read data from a text file into a tree all you need are the following two lines | ||
<code C++> | <code C++> | ||
- | TTree *myTree = new TTree(" | + | TTree *myTree = new TTree(" |
Long64_t nlines = myTree-> | Long64_t nlines = myTree-> | ||
+ | </ | ||
+ | |||
+ | |||
+ | === Dynamic Branche Names === | ||
+ | |||
+ | If you do not give the structure, the first line of your file must contain the tree definition | ||
+ | <code text input.csv> | ||
+ | bin: | ||
+ | 1 12 13 | ||
+ | [...] | ||
+ | </ | ||
+ | |||
+ | To use this tree you then need to get the branch names | ||
+ | <code C++> | ||
+ | TTree *myTree = new TTree(" | ||
+ | Long64_t nlines = myTree-> | ||
+ | |||
+ | TString col0Name = T-> | ||
+ | TString col1Name = T-> | ||
+ | TString col2Name = T-> | ||
+ | |||
+ | Float_t bin, | ||
+ | T-> | ||
+ | T-> | ||
+ | T-> | ||
+ | </ | ||
+ | |||
+ | === Dynamic Tree Structure === | ||
+ | You can extend this idea to plot all histograms in an unknown tree. | ||
+ | The following code reads a tree form a datafile with a arbitrary number of columns | ||
+ | and creats a histogram for each of them. | ||
+ | |||
+ | <code C++> | ||
</ | </ |